FORM2
THE PATENTS ACT, 1970
(39 of 1970)
&
The Patents Rules, 2003
COMPLETE SPECIFICATION
(See section 10; rule 13)
1. Title of the invention: A CONTACT SYSTEM FOR
SWITCHING DEVICES
2. Applicant(s):
(a) NAME : LARSEN & TOUBRO LIMITED
(b) NATIONALITY : An Indian Company
(c) ADDRESS : L & T House, Ballard Estate, Mumbai
400 001,State of Maharashtra, India
3. PREAMBLE TO THE DESCRIPTION
The following specification particularly describes the invention and the manner in which it is to be performed:

FIELD OF THE INVENTION
The present invention relates to a contact system for Switching devices. Particularly, the present invention relates to Switching devices which include Switches, Switch-Disconnectors, Switch-Disconnector-fuse, Changeover switches, etc which are primarily used to make and break the current supply to the downstream/load. More particularly the present invention relates to Contact system with bridge arrangement that provides linear opening and closing of contacts.
BACKGROUND OF THE INVENTION AND PRIOR ART
The Switch-Disconnector provides isolating function thereby preventing the flow of leakage currents that can harm the user. All the switches in general have a set of fixed contacts bridged by moving contacts to establish their function.
The bridge arrangements used in the present system have spring arrangements at the bottom of the moving contacts to provide the necessary contact pressure and their connection with the mechanism is linked in the area above the moving contacts. This type of arrangement occupies comparatively a higher amount of volume influencing the size of the product.
In existing system, the volume of bridge is not effectively utilized as the entire space above the moving contacts is used only for linkage with the mechanism. Also, high amount of space is used to house the spring below the moving contacts.
The invention provides a Contact system with a bridge assembly which is highly integrated that houses provision for establishing connection with the mechanism for its movement, provides a spring arrangement to deliver the necessary contact pressure, and also provides space for isolation between the poles. The arrangement is made such that there is complete utilization of the space available to the maximum extent.

Multiple functionalities in a single component enable high utilization of space with superior performance. It also facilitates the reduction in number of components and their linkages which in turn reduces the overall cost and chances of failure. As the major space of the switching device is occupied by the mechanism and contact system, it is necessary to reduce the size of the same. This invention would help in reducing the space occupied by the contact system thereby the overall size of the product by effective utilization of space available.
The present invention described here relates to a Contact system with bridge arrangement that provides linear opening/closing of contacts.
OBJECTS OF THE INVENTION
One object of the present invention is to overcome the disadvantages / drawbacks of the prior art.
A basic object of the present invention is to provide a Contact system with bridge arrangement that provides linear opening/closing of contacts.
These and other advantages of the present invention will become readily apparent from the following detailed description taken in conjunction with the accompanying drawings.
SUMMARY OF THE INVENTION
The following presents a simplified summary of the invention in order to provide a basic understanding of some aspects of the invention. This summary is not an extensive overview of the present invention. It is not intended to identify the key/critical elements of the invention or to delineate the scope of the invention. Its sole purpose is to present some concept of the invention in a simplified form as a prelude to a more detailed description of the invention presented later.

According to one of the aspect of the present invention there is provided a contact system for use in switching devices, said contact system comprising:
a housing;
a bridge assembly;
a mechanism component operatively connected with said bridge assembly;
fixed contacts;
said bridge assembly comprising:
atleast one spring holder having a substantially elongated bottom end and a substantially flattened profile top end profile of spring holder on the top ;
atleast one contact spring inserted within said elongated bottom end of spring holder;
atleast one bridge comprising a hollow cavity adapted for said elongated bottom end of spring holder to be inserted within said cavity of said bridge and making the other end of said spring holder accessible;
atleast one moving contact having a slot that matches with the bottom end of the spring holder, such that said bottom end of said spring holder inserted inside said slot of moving contact and then rotated 90 ° ; and
inter-phase barriers to isolate one pole from another comprises projections from said housing that acts as a sandwiching structure providing isolation between the poles.
Other aspects, advantages, and salient features of the invention will become apparent to those skilled in the art from the following detailed description, which, taken in conjunction with the annexed drawings, discloses exemplary embodiments of the invention.

BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWING
The following drawings are illustrative of particular examples for enabling methods of the present invention, are descriptive of some of the methods, and are not intended to limit the scope of the invention. The drawings are not to scale (unless so stated) and are intended for use in conjunction with the explanations in the following detailed description.
Figure 1 illustrates the exploded view of the bridge assembly.
Figure 2 illustrates the sequence of assembly.
Figure 3 illustrates the rear isometric view of the assembly with the moving
contacts in place.
Figure 4 illustrates the slanting profile in the bridge that is used to connect the
bridge assembly with the mechanism.
Figure 5 illustrates the sectional Front view of the Bridge assembly placed in the
housing.
Figure 6 illustrates the sectional bottom view of the Bridge assembly placed in the
housing during OFF condition of the device.
Figure 7 illustrates the sectional bottom view of the Bridge assembly placed in the
housing during ON condition of the device.
Figure 8 illustrates the sectional view of the Bridge assembly with Fixed Contacts
(7) when the device is in OFF condition.
Figure 9 illustrates the sectional view of the Bridge assembly with Fixed Contacts
(7) when the device is in ON condition.
Persons skilled in the art will appreciate that elements in the figures are illustrated
for simplicity and clarity and may have not been drawn to scale. For example, the
dimensions of some of the elements in the figure may be exaggerated relative to
other elements to help to improve understanding of various exemplary
embodiments of the present disclosure.

Throughout the drawings, it should be noted that like reference numbers are used to depict the same or similar elements, features, and structures.
DETAILED DESCRIPTION OF THE INVENTION
The present invention relates to a Moving Bridge in Contact system for Switching devices. The contact system comprising a housing; a bridge assembly; a mechanism component operatively connected with the bridge assembly and fixed contacts.
The bridge assembly comprises atleast one spring holder having a substantially elongated bottom end and a substantially flattened profile top end profile of spring holder on the top; atleast one contact spring inserted within the elongated bottom end of spring holder; atleast one bridge comprises a hollow cavity adapted for the elongated bottom end of spring holder to be inserted within the cavity of the bridge and making the other end of the spring holder accessible; atleast one moving contact having a slot that matches with the bottom end of the spring holder, such that the bottom end of the spring holder inserted inside the slot of moving contact and then rotated 90° and inter-phase barriers to isolate one pole from another comprises projections from the housing that acts as a sandwiching structure providing isolation between the poles.
The contact spring comprises compression spring. The bridge is having a slanting profile adapted to connect the bridge assembly with the mechanism. The spring force pulls the moving contact into its position and after the assembly, the assembled load of the spring prevents moving contact from releasing out of its slot.
The flattened profile top end profile of spring holder on the top is such that it cannot rotate after assembly preventing the Moving contact from falling off by its own/ during the operation.

The mechanism component moves linearly along the horizontal axis, the bridge assembly would move linearly in the vertical axis adapted to establish the linkage between the Mechanism and Contact system.
The housing is sandwiched inside the provision in the bridge thereby providing complete Inter-phase isolation maintained throughout the travel of the bridge assembly.
The mechanism pulls the bridge assembly upwards and establishes continuity of the circuit and the contact springs deliver the required pressure to the contacts through the spring holder when the switch is turned ON.
The mechanism component pushes the bridge assembly downwards to disconnect the supply when the switch is turned OFF.
DETAILED DESCRIPTION OF THE ACCOMPANYING DRAWINGS
The following description with reference to the accompanying drawings is provided to assist in a comprehensive understanding of exemplary embodiments of the invention as defined by the claims and their equivalents. It includes various specific details to assist in that understanding but these are to be regarded as merely exemplary. Accordingly, those of ordinary skill in the art will recognize that various changes and modifications of the embodiments described herein can be made without departing from the scope and spirit of the invention. In addition, descriptions of well-known functions and constructions are omitted for clarity and conciseness.
The terms and words used in the following description and claims are not limited to the bibliographical meanings, but, are merely used by the inventor to enable a clear and consistent understanding of the invention. Accordingly, it should be apparent to those skilled in the art that the following description of exemplary embodiments of the present invention are provided for illustration purpose only

and not for the purpose of limiting the invention as defined by the appended claims and their equivalents.
It is to be understood that the singular forms "a,'' "an," and "the" include plural referents unless the context clearly dictates otherwise.
By the term "substantially" it is meant that the recited characteristic, parameter, or value need not be achieved exactly, but that deviations or variations, including for example, tolerances, measurement error, measurement accuracy limitations and other factors known to those of skill in the art, may occur in amounts that do not preclude the effect the characteristic was intended to provide.
Glossary:
Switch:
A device designed to make or break the current in one or more electric circuits.
Fixed Contact:
A conductive part designed to establish circuit Continuity which is fixed to the housing where the termination is made.
Moving Contact:
A conductive part designed to establish circuit continuity which open or close a circuit through their relative motion during an operation.
Bridge assembly:
An assembly of moving contacts along with the springs that deliver the contact pressure that is connected with the mechanism of the device.
Contact pressure:
The pressure applied at the junction between the Fixed & Moving contacts to reduce the contact resistance and maintain continuity.

The Bridge assembly in the contact system described here has provision to accommodate,
- Moving contacts.
- Springs to deliver the required contact pressure (Contact springs) & Spring holders.
- Interphase barriers to isolate one pole from the other.
- Profile to connect the assembly with the mechanism.
The bridge assembly moves linearly by the force delivered by the mechanism through the slanting profile in the bridge & mechanism component. When the switch is turned ON, the mechanism pulls the bridge assembly upwards and establishes continuity of the circuit. In this condition, the contact springs deliver the required pressure to the contacts through the spring holder. When the switch is turned OFF, the mechanism pushes the bridge assembly downwards to disconnect the supply. During the movement of bridge assembly as well as in the ON/OFF condition, the provision for Interphase barriers houses the projection from the housing that acts as a sandwiching structure providing isolation between the poles.
Construction:
The main embodiment of this patent consists of Bridge assembly used in the contact system of Switching devices.
Figure 1 shows the exploded view of the bridge assembly.
The assembly consists of Spring holder (1), Bridge (2), Contact springs (3) and the moving contacts (4). The assembly shown is for a 3 pole device which can be extended similarly based on the number of poles required.
Figure 2 shows the sequence of assembly.
The contact springs (Compression springs that deliver the required contact pressure after switching ON the switch) are inserted into the spring holders as

shown. Then it is placed inside the bridge and pushed downwards so that the other end of the spring holder is accessible as shown. Now, the moving contact is inserted into the spring holder by matching the slot and rotated by 90 degrees. The spring force now pulls the moving contact into its position. After the assembly, the assembled load of the spring prevents moving contact from releasing out of its slot. The profile of spring holder on the top is such that it cannot rotate after assembly preventing the Moving contact from falling off by its own/ during the operation.
Figure 3 shows the rear isometric view of the assembly with the moving contacts in place. It also shows the provision for Inter-phase isolation.
Figure 4 shows the slanting profile in the bridge that is used to connect the bridge assembly with the mechanism. When the mechanism part (5) moves linearly along the horizontal axis, the bridge assembly would move linearly in the vertical axis as shown. This establishes the linkage between the Mechanism and Contact system.
Figure 5 shows the sectional Front view of the Bridge assembly placed in the housing. The housing (6) is sandwiched inside the provision in the bridge thereby providing complete Inter-phase isolation.
Figure 6 shows the sectional bottom view of the Bridge assembly placed in the housing during OFF condition of the device. The provision in the bridge (2) to house the Mechanism part (5) for the operation and the Inter-phase barrier from the housing (6) is clearly shown. The spring holder (1) with the Contact springs (3) & Moving contacts (4) is also shown.
Figure 7 shows the sectional bottom view of the Bridge assembly placed in the housing during ON condition of the device. It can be seen that the Inter-phase isolation is maintained throughout the travel of the bridge assembly.
Figure 8 shows the sectional view of the Bridge assembly with Fixed Contacts (7) when the device is in OFF condition. This makes up the complete contact system.

Figure 9 shows the sectional view of the Bridge assembly with Fixed Contacts (7) when the device is in ON condition. The Contact springs get compressed through the Spring holder thereby delivering the required Contact pressure as shown.
Advantages:
1. Provision for multiple features in a single Component (Bridge).
2. Effective utilization of available space.
3. Modularity and ease of assembly.
Features:
a) Multiple features in a single component (Btidge).
b) Increased space utilization without compromise on performance and functionality.
c) Modular.

WE CLAIM
1. A Contact system for Switching devices, said contact system comprising :
a housing;
a bridge assembly;
a mechanism component operatively connected with said bridge assembly;
fixed contacts;
said bridge assembly comprising :
atleast one spring holder having a substantially elongated bottom end and a substantially flattened profile top end profile of spring holder on the top ;
atleast one contact spring inserted within said elongated bottom end of spring holder ;
atleast one bridge comprising a hollow cavity adapted for said elongated bottom end of spring holder to be inserted within said cavity of said bridge and making the other end of said spring holder accessible;
atleast one moving contact having a slot that matches with the bottom end of the spring holder , such that said bottom end of said spring holder inserted inside said slot of moving contact and then rotated 90 ° ; and
inter-phase barriers to isolate one pole from another comprises projections from said housing that acts as a sandwiching structure providing isolation between the poles.
2. System as claimed in claim 1 wherein said contact spring is a compression
spring.

3. System as claimed in claim 1 wherein said bridge is having a slanting profile adapted to connect the bridge assembly with the mechanism.
4. System as claimed in claim 1 wherein said spring providing force to pull said moving contact into its position and after the assembly, the assembled load of the spring prevents moving contact from releasing out of its slot.
5. System as claimed in claim 1 wherein said flattened top end profile of spring holder on the top is such that it cannot rotate after assembly preventing the Moving contact from falling off by its own/ during the operation.
6. System as claimed in claim 1 wherein said mechanism component moves linearly along a horizontal axis.
7. System as claimed in claim 1 wherein said bridge assembly moves linearly in the vertical axis to establish the linkage between the Mechanism and Contact system.
8. System as claimed in claim 1 wherein said housing is sandwiched inside the provision in the bridge thereby providing complete Inter-phase isolation maintained throughout the travel of the bridge assembly.
9. System as claimed in claim 1 wherein said mechanism pulls the bridge assembly upwards and establishes continuity of the circuit and the contact

springs deliver the required pressure to the contacts through the spring holder when the switch is turned ON.
10. System as claimed in claim 1 wherein said mechanism component pushes the bridge assembly downwards to disconnect the supply when the switch is turned OFF.